JPS60195410A - External size measuring instrument of channel box - Google Patents

Abstract

PURPOSE:To execute exactly a measurement by considering the speed of sound corresponding to a water temperature by installing a distance detecting body and a sound speed detecting body to a freely liftable sensor supporting base by a specified arrangement, and deriving an external size by using the speed of sound calculated from the time measured by both the detecting bodies. CONSTITUTION:An external size measuring instrument 10 of a channel box 3 is constituted of an external size measuring means 11 and an operating means 21, and the means 11 is constituted by installing a sensor supporting base 16 so as to be freely liftable on a guide body 17 fixed and provided on a side face 1a of a used fuel storage pool 1, and installing a distance detecting body 13 and a sound speed detecting body 15 to the base 16. Also, the detecting body 13 is constituted by providing a suitable number of ultrasonic sensors 12 provided on a straight line, in a shape of L so that its transmission is reflected each other from the box 3, the detecting body 15 is constituted by providing a pair of ultrasonic sensors 14 so that one executes a transmission and the other executes a reception, and an external size of the box 3 is derived by correcting a distance measured by the detecting body 13, by the speed of sound by the detecting body 15.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device for measuring the external dimensions of a channel box of a nuclear fuel assembly for a boiling water reactor.

(Prior Art) The external shape of the channel box may be measured after irradiation for purposes such as follow-up of irradiation characteristics.

Therefore, conventionally, the external dimensions of the channel box have been measured using an underwater television device or the like as necessary, but the measurement work and the processing of the measurement results are complicated.

Therefore, as a method to compensate for this drawback, a method of measuring the external dimensions of a channel box using ultrasonic waves is considered.

This method applies ultrasonic waves sequentially emitted from an appropriate number of ultrasonic sensors installed vertically on a support frame along the channel box to each measurement position of the channel box, and receives the waves reflected by the channel box. This can be done by measuring the time it takes to

In other words, the distance from the transmitting/receiving surface to several points at one measurement position is calculated individually in the time until reception, and this is performed for each measurement position to calculate the external dimensions of the channel box in the longitudinal direction. .

However, when a fuel assembly exists in a channel box, the spent nuclear fuel assembly usually emits decay heat, and the calorific value is not uniform in the longitudinal direction of the nuclear fuel assembly, which makes it difficult to store spent fuel. The water temperature distribution around the channel box in the pool is uneven.

However, although the measurement uses an ultrasonic sensor, it does not take into account the difference in sound speed that changes depending on the water temperature. Therefore, since the travel time detected by the ultrasonic sensor is measured based on the sound speed corresponding to the water temperature at each measurement position, the outer shape over the entire length of the channel box calculated based on the measurement time up to each measurement position is Dimensions do not represent actual external dimensions.

(Object of the Invention) The present invention has been made to solve the above-mentioned problems, and when measuring and calculating the external dimensions of channel boxes with different ambient water temperature distributions in a spent fuel storage pool, it is necessary to An object of the present invention is to provide an apparatus for measuring the external dimensions of a channel box that can perform accurate measurements while taking into account the speed of sound.

3- (Structure of the Invention) That is, the present invention is characterized by a distance detecting body in which an appropriate number of ultrasonic sensors arranged in a straight line are arranged in a horizontal plane, and a distance detecting body that is exactly the same as this distance detecting body. A sound velocity detection body consisting of a pair of ultrasonic sensors arranged in a plane so that transmission from one side is received by the other is mounted on a sensor support stand that can be raised and lowered on a guide body erected in the vertical direction. The external dimensions of the channel box are estimated using the external dimension measuring device installed in each of the above positions, the sound velocity calculated from the time measured by the distance detector, and the time measured by the sound velocity detector. The present invention has an external dimension calculation means.

(Example) Hereinafter, specific embodiments of the present invention will be described in detail in sequence based on the accompanying drawings.

FIG. 1 is a diagram showing the external dimension measuring bag M (10)' of the channel box according to the present invention in use when installed in the spent fuel storage pool (1), and shows the external dimension measuring bag M (10)' of the channel box according to the present invention. Suspended along the pool wall (1a) 4
- It is installed so as to face the channel box (3).

As is clear from the figure, this measuring device 00) mainly includes an external dimension measuring means (11) for measuring the longitudinal external dimension of the channel box (3), and a measuring device (11) for measuring the external dimension of the channel box (3) based on the measured value. It consists of calculation means (21) for calculating actual external dimensions.

Among these, the external dimension measuring means (11) is the basic measuring device of the present invention, and its details are as shown in FIG. Distance detecting body 03) is arranged to be orthogonal to each other in a horizontal plane so that its transmission is reflected from the side of the channel box (3), and one of the distance detecting bodies 03) is disposed on the same plane as the distance detecting body 03). A sound velocity detection body C15) consisting of a pair of ultrasonic sensors 0→, the other of which receives this signal, is mounted on a sensor support stand 06).

This sensor support stand (16) has a planar shape of
.

The spent fuel storage pool (
It is mounted so as to be able to rise and fall freely on the guide body θη fixedly erected on the entire surface (1a) of 1), and can be moved to a position corresponding to the measurement position of the channel box (8) carried in to be adjacent thereto. ing.

and a storage pool (1) near the guide body 0'7).
An operation panel (19) for commanding the transmission and reception of ultrasonic waves at the ultrasonic sensor 02) and O→ is provided above.

In addition to the above configuration, a distance detection device similar to that described above is separately installed above or below the movable sensor support base 06) at a position corresponding to the second part or the bottom of the channel box (3). body 03) and sound velocity detection body (
15) on the sensor support stand equipped with the guide body 07).
) is also preferable, and the external dimensions of the swinging channel box (3) can also be measured as described later.

On the other hand, the external dimension calculation means eυ calculates the external dimensions of the channel box (3) with temperature correction based on the time measured by the distance detector θ3) and the sound velocity detector (b). Yes, usually installed above ground above the pool.

The present invention has the configuration as described above, and its operation will be explained next.

In Figure 1, first, the spent fuel storage pool (1)
Inside one of the channel boxes (3), the storage pool (
1) Suspend the fuel exchanger (2) that runs above the wall (1).
Transfer to external dimension measuring device θ0 provided near a). In this case, since the measuring device (10) has a diagonal planar shape, it can be placed adjacent to each other very easily.

Next, when the swinging due to the transfer of the channel box (3) stops, the operation panel 09) moves the channel box (3)
Ultrasonic waves are emitted from the ultrasonic sensors (to) of the distance detector 03) and the sound velocity detector 05) mounted on the sensor support stand 06) facing the sensor.

At this time, the ultrasonic sensor 02 of the distance detector cps>
The ultrasound waves from the side (4) of the channel box (3)
) and the time it takes for it to be received again is measured. Simultaneously with this measurement or with a slight time delay, the time until the reception of nl transmitted from one ultrasonic sensor 0 to the other ultrasonic sensor of the sound velocity detector (b) is measured.

7- In addition, as shown in Figure 2, if the ultrasonic waves from the ultrasonic sensor 0 are brought close enough that they do not hit the channel box (3), the ultrasonic waves from the ultrasonic sensor 02) will propagate. Area measurements can be taken, and
If the mounting positions of the ultrasonic sensors 0→ are placed as far apart as possible (Lo in the figure), the time required to increase the speed of sound becomes longer, and the measurement accuracy can be improved accordingly.

In this way, the sensor support base 06) is successively moved to the required measurement positions by an elevating drive device such as an air cylinder, and measurements are performed at those positions. When the measurement of all two sides of the measurement site facing the sensor support stand 06) is completed, the channel box (13)
Flip it 180 degrees and measure the other two sides at each measurement position. At this time, if observation using the underwater television camera e31 is required, the sensor support stand Oa) may be moved together with the underwater television camera head @).

The time measured by the above-mentioned ultrasonic sensor (b), 0→ is calculated by the computer of the external dimension calculating means CI).
- the external dimensions are calculated based on said time.

That is, based on the time t1 measured by the ultrasonic sensor 0→ and the distance between the ultrasonic sensors -0→, which are installed in advance at an interval of LO, the speed of sound at that point can be determined as Lo/lt. Note that if the correlation between water temperature and sound speed is known as shown in FIG. 3, the sound speed may be determined by directly detecting the entire water temperature using a temperature sensor or the like. By multiplying this sound speed by the one-way time T1/2 to the measurement position measured by the ultrasonic sensor (B), the true distance to the measurement position (Lo·T1/2t1) is calculated. Therefore, if we measure the distances at several locations at each measurement location and calculate the relative positions of each location, Figure 4(a)
, As shown in (b), the external dimensions of the channel box (3) in the longitudinal direction can be calculated.

In addition, above or below the sensor support stand 06) that moves up and down as described above, a distance detector (I3) and a sound velocity detector 05) similar to those described above are placed at positions corresponding to the upper or lower part of the channel box (3). If the fully attached sensor support stand (A) is installed, even if the channel box (3) is slightly swaying, it is possible to measure the distance of one of the measurement positions mentioned above at the same time as measuring the position of the lower part of the channel box (3). If this is done, the external dimensions can be measured using the lower part as a reference.

Thus, the external dimensions of the channel box can be accurately measured using the measuring device of the present invention.

``%Rj鵠〜effect＼ に'' Second, we explained the case of a distance detection object in which the ultrasonic sensors are arranged orthogonally to each other, but the distance detection object 03)
For example, as shown in Fig. 5, the ultrasonic sensor (b)) is placed only on the - line on the sensor support stand 06), and the ultrasonic sensor (b)) is placed only on the - line. )'s ultrasonic sensor 0→, a distance detecting body in which an appropriate number of ultrasonic sensors are arranged in a horizontal plane, and the ultrasonic sensors are arranged opposite to and together with the channel box (3);
This distance detecting body includes a sonic velocity detecting body consisting of a pair of ultrasonic sensors arranged on the same plane, and a guide body mounted with this sonic velocity detecting body and the distance detecting body and installed in the vertical direction.
- a channel box using an external dimension measuring means having a sensor support that can be raised and lowered at The external dimension calculating means calculates the external shape of the channel box, so that the external dimensions of the channel box under different ambient temperatures due to the decay heat of the spent nuclear fuel assembly, etc., can be calculated by synergistically measuring the measurement time by the rain detector. It can be measured as the true external dimension.

Moreover, in the above device, since the sensor support base is movable up and down, there is no need to arrange a large number of ultrasonic sensors, the configuration is simplified, and the measurement operation on the operation panel is also simplified. In addition, there is an advantage that measurement can be performed on any part of the channel box depending on the stopping position of the sensor support, and this method is extremely useful in improving measurement accuracy in measuring the external dimensions of the channel box. Note that the measuring device can also be applied to fuel assemblies.

[Brief explanation of drawings]

Figure 1 is an installation diagram of the external dimension measuring device of the present invention, Figure 2 is a plan layout of the external dimension measuring means, Figure 3 is a diagram of the correlation between water temperature and sound speed, and Figures 4 (a) and (b). 5 is a diagram illustrating the state of measurement of the external dimensions of the channel box, and FIG. 5 is a plan view showing another embodiment of the ultrasonic sensor arrangement. (3)・・・・・・Channel Bokkun. 00)...External dimension measuring device. 01)... External dimension measuring means. 02) (2)...Ultrasonic sensor. 03)... Distance detecting object. 05)...Sound velocity detector. 06) (a)...Sensor support stand. 07)・・・・・・Guidance body. 011... External dimension calculation means. Government 1 figure Police 7F3 figure Water temperature 0c 7t5 figure

Claims (1)

[Scope of Claims] ■. A distance detecting body in which an appropriate number of ultrasonic sensors arranged in a straight line are arranged in a horizontal plane, and this distance detecting body is on the same plane, and the transmission from one side is A sound velocity detection body consisting of a pair of ultrasonic sensors arranged so that the ultrasonic waves are received by the other is mounted in the above arrangement on a sensor support stand that can be raised and lowered on a guide body erected in the vertical direction. Using the dimension measuring means, the time measured by the distance detector, and the speed of sound calculated by the time measured by the sound velocity detector,
1. A device for measuring external dimensions of a channel box, comprising: external dimension calculation means for calculating external dimensions of the channel box. 2. The device for measuring external dimensions of a channel box according to claim 1, wherein the sensor support base has a square shape in plan view. 3. External dimensions of the channel box according to claim 1 or 2, wherein the sensor support is integrally constructed with an underwater television camera head mounted on the guide body so as to be able to rise and fall freely. measuring device. 4. Fix a sensor support stand with the same configuration as the sensor support stand on which both of the detection bodies are attached to the position corresponding to the upper and/or lower part of the channel box, and measure the external dimensions of the static II- or swinging channel box. A channel box external dimension measuring device according to any one of claims 1 to 8, which is capable of measuring.